Sub-μWRComm: 415-nW 1–10-kb/s Physically and Mathematically Secure Electro-Quasi-Static HBC Node for Authentication and Medical Applications

Low-power secure communication is one of the key enablers of applications, such as secure authentication and remote health monitoring. Radio wave-based communication method, such as Bluetooth, suffers from high-power requirements and physical signal leakage. Electro-quasi-static human body communication (EQS-HBC) utilizes the conductivity of the human body to use it as a communication medium and confine the signal within a close proximity of the body and enable low power consumption through low-frequency operation. This makes EQS-HBC an attractive alternative for such low-power, low-data-rate secure communication. In this article, we present the first >1 kb/s Sub- μ W WeaRable Communication (Sub- μ WRComm), a secure EQS-HBC node, which uses EQS-HBC for physical security and an AES-256 engine for mathematical security and operate at sub-$\mu \text{W}$ power budget. The signal confinement property of EQS-HBC is demonstrated through finite element method (FEM) simulations and leakage measurements, establishing its security property. The Sub- μ WRComm system consumes only 415-nW total power, with 108-nW active power at the lowest power mode, operating at a data rate of 1 kb/s with -64-dBm sensitivity making it suitable for authentication and remote monitoring applications. This work presents a 100x improvement compared with state-of-the-art HBC implementations while providing simultaneous physical and mathematical security for the first time.